Concentration of ores



Patented Jain. 11, 1527. 1,614,089 UNITED STATES PATENT OFFICE.

JAMEsn. s'rnvnns. or HAYDEN, Anizoim.

, CONCENTRATION OF ORES.

Ho Drawing. I i Application filed July 1, 1926. Serial No. 119,998.

This invention relates to the concentration successfully carried out without the emof ores, minerals, and the like, by flotation, p'loyment of foreign frothing agents, such and hasfor its object the provision of cer- 'as pine oil or the like. For example, an ore tain improvements in the flotation processes, pulp containing about 1.24% copper was and more particularly the froth flotation sub ected to agitation, and acid (H SO no processes added at the rate of pounds per ton of The present invention is based upon a solids Amyl sulphocyanide was then added discovery that improved results may be obat the rate of about .8 lb. per ton of solids. tained by the use in flotation of certain or- Upon adding the amyl sulp hocyanide a ganic nitrogenous compounds containing voluminous, heavily mineralized froth was 05 sulphur, in which the (N) nitrogen is in the formed, which was removed from the form of (CN) cyanogen, and the(S) sulgangue pulp by allowing same to overflow phur is in combination therewith, forming the flotation cell. The concentration in this the radical SON in compounds commonly operation was sufiicient to reduce the tailknown as sulphocyanides (or sulphocyaings to 0.10% copper and produce a con-' nates). In certain cases these compounds centrate containing about 13.0% copper. may have a formula of R SCN in which B This operation was conducted without the is an organic radical, such as an alkyl radiaid of a foreign frothing agent. a

cal. Various wellknown methods may be em- 20' While the general formula of R SCN is ployed to produce normal alkyl sulphocya- To ,7 given to show the constituents' of the com-. nides, which have the general formula 11- pounds covered by this specification, the S-CEN, In these compounds the cyanoscopclof this inventwn in its broadest. a gen radical is linked to the alkyl radical by pect is not limited to any particular method sulphur. However, Ihave found that vari ular structural formula or arrangement of propertie may b btained b introducing atoms in the molecule, asyl have found that the sulphocyanide radical (S N) into varivarious reaction products possessing valuous organic compounds by a simple method able flotation properties and also possessing of interaction of an acid; -For example, I

3 various chemical and physical properties have found that by first treating an alcohol have resulted from various means of reacwith an aoid,si1ch as, for example, sulphuric tion as is hereinafter describe acid, or commercial aqueous hydrochloric Alkyl sulphocyanates (or sulphocyanides) acid, and adding t this mixture a salt of may be prepared by various wellknown sulpho-cyanic acid, such as potassium sulnormal amyl sulphocyanate by distilling mixture tovarious degrees of'heat, say from amyl sulphate with potassium sulphoc'yaatmospheric temperature up to the boiling nateL, The distillate from this mixture was temperature of the compound, various chem} v of an oily character, only slightly soluble ical products ma be formed, some of which 40 in water and giving a deep red reaction do not possess t e properties of normal a1 05 with ferric sulphate. This compound, kyl sulphocyanides and yet possess valuable when employed as a, flotation reagent for flotation properties. For example, 98 parts of chemical combination nor to any particous compounds possessing valuable flotation 8 0 methods; for example, I have prepared phocyanate. (KGNS) and subjecting the recovery of the metalliferous constituents by weight of concentrated sulphuric acid from the gangue minerals of an ore pulpg were slowly added to 74 parts by weight of v roduced. a voluminous, well 'mineralized butyl alcohol. Considerable heat of reac- 100' froth, exhibiting a very marked selective ac; tion was produced by this mixture. The tion on sulphide minerals. This compound -mixture was cooled and 97 parts by weight apparentlyfunctions best when used in conof potassium sulphocyanate in crystalline junction with asmall amount of an "acid formadded thereto. The mixture was agi- 50 (for example, sulphuric acid).

Amyl sulphocyanate possesses valuable 'of'water. The resultant product from this frothin'g properties. The frothing'propermixture was very soluble in water, and.

, ties of. this compound, together. with its while this compound showed no evidence of J a marked selective action on sulphide minerthe presence of normal butyl sulphocyanide,

tated and diluted with lOO parts by weight als, enablethe froth flotation process to it possessed a marked selective action on sulg phide miueralsrwhen used in the customary flotation processes. A flotation test conducted on an ore pulp, using .the above diluted product at the rate of about .5 lb. per ton 5 of solids, and pine oil at the rate of about .15 lb. per ton, gave the following metallurgical results: r

i Per cent copper. Heading 1.12 Tailings 0.11 Concentrates 11.30

99 The mixtures were then heated gently and mhi) 5 ous minerals, particularly sulphide minerals.

In other tests in which I have employed acid for the purpose of combining" or asso-' ciating the radical of sulphocyanide ('SCN M with alcohols, the following procedure was used: Mixtures of sulphuric acid and alcohols were brought to a boiling temperature and then cooled. Potassium sulphocyanate in crystalline form was then added.

As an example of the above procedure, 100 parts of denatured ethyl alcohol- (formula N0. 5 were treated with 98 parts by weight of concentrated sulphuric acid. The mixture was lheated to a boiling temperature and then cooled in an ice bath. 97-parts by weight of potassium sulphocyanate in crystalline form were then added. The mixture was heated gently, agitated until a homogen'eous paste was formed; and then disa tilled. ,This method of combination has been applied to various other alcoholic compounds, for example, propyl, butyl, and amyl alcohols, the. products of which were similar in each case to the above described compounds.

From-the foregoing example, it is seen that an excess of alcohol, above the theore'tical amount required for the reaction, was

used. This excess of "alcohol was usedin order to prevent the presenceof any large amount of free acid, asthe reaction between i tlieiic-id and alcohol is a reversible one, es-' to pecially when subjected to heat. In general,

therefore, it is advisable to use an excess of 2 alcohol and reduce the mixtureof alcohol and ,acidto a low temperature prior to addingthe potassium sulphocvanate. An excess ls of free acid {in the mixtures should; ,be-

avoided as far as possible as the free acid may cause complete decomposition of the potassium sulphocyanate be caused to be very effective in separating the metalliferous minerals from the ganguc minerals by flotation. this, I have introduced sulphocyanide into pipe oil. Approximately 300 parts by .weight of pine oil weretreated with, 98 parts by weight of sulphuric acid. Considerable v heat was produced by this mixture and no additional heat was applied; The mixture, after being agitated a few minutes, was cooled,and 97 parts by weight of potassium sulphocyanate added. 'The mixture was thoroughly shaken and allowed to "stand about one hour and then distilled. The complex compounds or mixtures contained in As an example of the distillate from this procedure possessed marked selective properties as well as the ordinary frotliing properties of the pine oil.

I have also caused sulphur and cyanogen to be introduced into or combined with cresol or cresylic acid, which'is also a frothing oil, and have found that products having the properties of sulphocyanides may be so produced and that these products give'good results in flotation operations. For example, I have treated 300 parts by weight of reresylic acid with 98 parts by weight of sulphuric acid, and have then treated the product of this reaction, after a short agitation followed by cooling, with 97 parts by Weight of'potassium sulphocyanate, The mixture was shaken and allowed to stand and then distilled. The resulting distillate showed distinetive, selective properties when used in flotation operations, in addition to the ordinary frot-hing properties of the cresyliic acid.

From the foregoing examples, it is seen that my invention in its broadest sense contemplates the use in flotation of organic compounds containing a radical of sulphocy- .anide. More specifically, the invention contemplates on the one ,hand', the" use in flotation of 'normal sulphocyanide compounds having the general formula R S GEN, in which B may represent an alkyl orother organic radical, such as the radicals contained in pine oil; and on the other hand, the use of agents formed by thecombination of the -or by the introduction of the sulp ocyanide p sulphocyanide radical with an alk l radical,

radical'into frothing oils, such as pine oil,

, whether or not the resulting compounds are normal sulphocyanides.-

' The following table shows the metallurgical results pf flotation tests conducted on samples of ore pulp from the Ray Consolidated Copper Company, at Hayden, Arizona.

The various materials into which the sulphocyanide was introduced, (a) ethyl alcohol, (b) prop 1 alcohol, (a) butyl alcohol, (d) amyl alcohol, (6) fusel oil, f) pine oil, and cresylic acid, were treated with sulphuric acid, potassium. sulphocyanide added, and the mixtures distilled as has previously been described. The tests were conducted with the distillate in each case.

Rougher conets., Cu.

Ro z er tailings, Cu.

Note: Pine oil was added in tests, a and b. Tests 0, 1 d, e, f, and g were conducted without the aid of additional frothing e, and (fwere conagents. Tests 0, b, 0, (Z,

slightly acid with ducted in a pulp made sulphuric acid. Test f was conducted in an alkaline pulp. 1

I have specified potassium sulphocyanate as a source of obtaining the (SCN) sulphocyanide. The sulphocyanide may; however, be derived from any suitable source. I have for example, employed sodium sulphocya hate as a substitute cyanate. v

I have described, in'detail, several methods which may be-employed in making the Iotation agents herein described, however, any suitable method of combination or reaction may be used.

The chemical. and physical properties of the compounds covered by. this specification may vary dver a wide range. For example, in some cases, the compounds are very oleagfor the potassium sulphoinous, while in other cases they are nonoleaginous.

Also in some cases the compounds possess valuable frothing propertiestogetherwith their marked selective action. In some cases these compounds do notpossess frothing properties, and it is necessary to supplement their selective action with a 'frothing agent. Furthermore,

7 these compounds possess various degrees of S0ll1b1l1ty in water, ranging from compounds that are =,readily and completelysoluble in water to compounds that are's'nhstantially'insoluble in ject the reagents between the the surface of the mineral particles andthe water. Essentially, however, these comounds must 'contain sulfur and cyanogen substantially as described.

In applying the reagents herein described, they may be introduced into the ore pulp in any suitable way; for instance, they may be introduced into the tube millin which the ore is being ground or may ore pulp just before it enters the flotation cell. In general, however, I prefer to subto agitation with the ore pulp prior to entering the flotation cell.

The amount of the reagents of the present invention, required for effecting the concentration of ores may vary somewhat. For example, in treating ordinary clean sulphides the amount may be or less per ton of ore, pound per ton of ore.

to approximately one In treating mixed oxide metalliferous minerals, it may be advisable to use a larger quantity than is required for cleansulph'ide ores. The reagents herein ployed as flotation agents in acid, neutral or alkaline ore pulps'. In general, however, I prefer ence of an acid electrolyte, such as, for example, sulphuric acid. Other neutral or acid electrolytes, such as calcium sulphate, acid or neutral sodium or potassium sulphates in solution with water, may be added in any suitable manner. Thus the alkali metal salts derived from reactions in the formation of some of the compounds of the present invention may advantageously be employed in conjunction with the selective agents, reducing the additional quantities of acids or salts re uired, and also eliminating the necessity o segregating or purifying the products of reaction. The acid may be added to the ore pulp before or after adding the selective agent, I

In general, it is characteristic of the compounds of the present invention to cause the mineral particles to be firmly attached to the bubbles forming the froth, and'in this respect showing a more intimate relation action of these compounds on froth, than has been noticed with other compounds reviously employed. 7

It wil be understood by those skilled in the art that the present invention is applicable to the treatment by flotation of various kinds of mineral mixures,.both natural and artificial; In the appended claims I have accordingly employed the termmineral pulp in a broad sense to include mineral products and all materials amenable to concentration or similar treatment by the fiota tion processes. I

While I have mentioned the marked selective action of these compounds upon sulphide minerals, the results obtained by he added to the varied from pound described may be em to employ these reagents in the pres thereby lit) their use in flotation have also indicated a strong selection for oxidized metalliferous an alkyl sulphocyanide compound and then subjecting the pulp to a froth flotation operatlon.

4. The method of concentratlng minerals which comprises adding to the mineral pulp a sulphocyanic ester of a higher alcohol and then subjecting the pulp to a froth flotation operatio 5. The method of concentrating minerals which comprises adding to the mineral pulp a flotation agent comprisingbutyl sulphocyanide and then sub ecting the pulp to a froth flotation operation.

6. The method of concentrating ores or other material which consists in treating a pulp containing such materials with a compound containing an alkyl radical together with sulfurand cyanogen and then subjecting the pulp to a froth flotation operation.

The method of concentrating ores or other material which consists in adding to a pulp containing such material, an organic compound containing sulfur and cyanogen, and subjecting the pulp to froth flotation in the presence of such compound.

' 8. The method of concentrating minerals which comprises adding to the mineral pulp a flotation agent produced by treating an alcohol with acid and with a sulphocyanate salt, and then subjecting the pulp to a froth flotation operation.

9. The method of concentrating minerals which comprises adding to the mineral pulp a flotation agent produced by treating an alcohol with sulphuric acid and with a sulphocyanate salt, and then subjecting the pulp to a froth flotation operation.

10. The method of'concentrating minerals which comprises adding to the mineral pulp a flotation agent produced by treating higher aliohol with acid and with a sulphocyanate salt, and then subjecting the pulp to a froth flotation operation.

11. The mcthod of concentrating minerals which comprises adding to the mineral pulp a flotation agent produced by treating butyl alcohol with acid and with a sulphocyanate salt,'and then subjecting the pulp to a froth flotation operation.

152. The method of concentrating minerals which comprises adding to the mineral pulp a normal sulphocyanide of an organic compound and also adding thereto an electrolyte,

and then subjecting the pulp to a froth fiotation operation.

13. The method of concentrating minerals j which comprises adding to the mineralpulp an organic sulphocyanide compound and also adding thereto an acid electrolyte, and then subjecting the pulp to a froth flotation operation.

14. The method of concentrating minerals by flotation which comprises adding to the mineral pulp an alkyl sulphocyanide comound, and also adding thereto an electroyte,and then subjecting the pulp to a froth flotation operation.

15. The method as set forth in claim 14, said electrolyte being an acid electrolyte.

In testimony whereof I have hereunto subscribed my name this 25th day of June 1926.

JAMES L. STEVENS. 

